The present invention relates to a process for manufacturing a gas flow unit.
A hollow gas flow unit such as rocket nozzle for allowing high-temperature gas to flow through is designed to have means for cooling the unit itself.
Referring to FIG. 1, a conventional hollow gas flow unit will be briefly explained which is a heat exchanger or rocket nozzle as disclosed in Japanese Utility Model 1st Publication No. 61-78263.
An inner cylinder 1 with a gas passage 2 comprises two concentrically laminated, substantially cylindrical electrocast copper layers 3 and 4 with coolant passages 6 being defined by the layer 4 and grooves 5 on the layer 3.
A two-split type outer cylinder 7 made of a heat-resistant alloy is fitted over and joined to the inner cylinder 1 by welding or the like. The outer cylinder 7 has, at its opposite ends, manifolds 8 and 9 which are in communication with the passages 6.
When high-temperature gas is to flow through the passage 2 in the above-mentioned heat exchanger, coolant is introduced through one manifold 8 into the passages 6 to cool the inner cylinder 1. The coolant with increased temperature due to cooling of the cylinder 1 is discharged out of the passages 6 through the other manifold 9 so that any temperature rise in the cylinder 1 is suppressed.
In the above-mentioned heat exchanger, the cylinders 1 and 7 are joined together by welding or the like only at their opposite ends so that the outer cylinder 7 must be designed to have a thicker wall capable of enduring any pressure of the coolant flowing through the passages 6 as well as most of the pressure of the gas flowing through the passage 2, resulting in increase of weight of the heat exchanger as a whole.
Because of the cylinders 1 and 7 being joined together by welding or the like, the layers 3 and 4 may separate from each other due to any local heat, resulting in leakage of the coolant.
The present invention was made in due consideration to the above-mentioned problems and has its object to provide a process for manufacturing a gas flow unit which contributes to reduction in weight of a gas flow unit, prevents separation of electrocast layers and excludes leakage of the coolant.